As is known, conventionally mechanical actuation of a weaving loom is performed by means of a main motor connected to a main shaft of the loom. The term “main shaft” is therefore understood as meaning the shaft which provides the motion to the main weaving components of the loom, such as the sley and reed, the grippers or the weft insertion nozzles, other devices such as the weft supply device, cutters, tensioners and, finally, the weave machine as well.
Normally the weave machine can be engaged with and disengaged from the main shaft and a secondary motor is also envisaged, said motor being connected to the weave machine by a respective coupling device and which is used to find the pick and move the whole loom in a slow running condition. Precisely in order to satisfy this requirement, it is known to use a coupling system comprising clutch, brake and flywheel between the main motor and the weaving mechanism and the weave machine.
It has also been proposed to simplify considerably this basic structure, by eliminating the secondary motor and the main coupling device with the associated flywheel.
A known device is, for example, that described in European patent application No. 01112634.9, in which it is taught to use a single motor connected, via a continuous drive, to the weave machine and able to drive, by means of an engageable and disengageable transmission, the other weaving components of the loom as well.
These solutions, however, have certain drawbacks. In particular, the dimensions of these actuating assemblies are considerable and occupy their own position on the loom which cannot be used in any other way. Moreover, the provision of the coupling devices involves design, manufacture and maintenance costs.
Moreover, the actuating assembly is normally located on one of the two sides of the loom and therefore imputs torques at one end only: this means that the torque moments which are generated on the transmission members of the loom, especially if the latter is fairly high, are considerable. This characteristic is such that the transmission shafts which extend over the whole height of the loom (for example the sley-actuating cam shaft) must be designed with appropriate dimensions and suitably supported, i.e. it is required to use large sections (=more material and greater weight) and a plurality of supports which-interfere with the other components of the loom.
Moreover, the angular deformations and strains of these shafts produce angular offsets of the ends of the shafts and result in abnormal displacements of the weaving components actuated by these shafts. For example, the torsional force acting on the cam shaft actuating the sley may result in a difference of displacement between the two ends of the reed which as a result does not move perfectly perpendicularly with respect to the warp yarns, causing inevitable weaving defects.
The object of the present invention is to provide an arrangement of the assembly for actuating the weaving mechanism which overcomes the drawbacks described above.
In particular, it is provided to simplify the series of components forming the loom actuating mechanism in order to reduce the inertial phenomena (thus increasing, among other things, the rapidity of response during the start-up and stoppage transients); ensure the symmetry of the general structural lay-out, in particular the resistive and applied loads, so as to optimise the structural response of the loom to the dynamic actions; and reduce the dimensions and the structural complexity, so as to achieve also savings in terms of costs.